Max Mazurov

I'm slowly getting some pieces together in [this repo](https://github.com/foxcpp/go-jmap).

Status update: JMAP is a big complex protocol that is not used by any popular clients and has no server libraries available for Go. IMAP is a big complex but...

It is definitely helpful to have some known-working code to look at. Thanks for your work!

>the maddy_* prometheus metrics don't seem to appear in the /metrics output until they actually get incremented (maybe this is intentional? But as a Prometheus noob I would have liked...

>I can have a crack at these problems if you don't think I'm wrong. Oh, I must have missed completedTransactions. >excluding ones received from local users I guess a bunch...

Working on this as part of improving maddy's DSN generation logic.

>How does postfix handle this? I feel like I've seen a message/DSN before that it 'failed but will keep retrying'. I believe default postfix behavior is to keep trying silently...

It may be reasonable idea to send such notification only when 2 attempt fails since many small-scale servers implement greylisting so first attempt will almost always fail.

If someone wants to jump in and implement it before I get a chance: 1. Improve human-readable message formatting to mention "will keep trying" if status is Delayed: https://github.com/foxcpp/maddy/blob/fe973563958f382411074a38b44fb5dc1fe80503/internal/dsn/dsn.go#L292 2....

Things to be abstracted out from queue code are: 1. Scheduler Determines when message delivery should be attempted. Interface is roughly this: ```go Schedule(time time.Time, attemptId string) Wait() (attemptId string)...